1. Field of the Invention
The present invention relates to an original document presser adapted for image forming apparatus such as a copying machine, printer, recording apparatus, etc. In particular, the present invention relates to such original pressing apparatus in which an original document pressing member is automatically opened and closed.
2. Description of the Prior Art
A conventional image forming apparatus such as a copying machine usually includes a pressure plate for pressing a sheet original or a book original closely on an original table or carriage so as to prevent the original illuminating light from entering other portions besides the original document placed on the original table. Otherwise, portions other than the original may be undesirably copied in black which will degrade the quality of the copy then produced.
Recently, in order to improve the manoeuvrability of a copying machine, such a pressure plate has often been mounted in such a manner that the pressure plate is opened and closed automatically. However, such an automatically opening and closing pressure plate has some problems. When the pressure plate is moved down to its closed position on the original table or carriage at a high speed, the original once correctly placed on the original table is sometimes displaced by the impact of the pressure plate against the original. This is one of the important practical problems involved in the known automatically operable pressure plate.